From: Tejun Heo <htejun@gmail.com>
Date: Wed, 5 Dec 2007 07:43:10 +0000 (+0900)
Subject: libata: change ATA_QCFLAG_DMAMAP semantics
X-Git-Tag: v2.6.25-rc1~1233^2~26
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f92a26365a72333f418abe82700c6030d4a1a807;p=pandora-kernel.git

libata: change ATA_QCFLAG_DMAMAP semantics

ATA_QCFLAG_DMAMAP was a bit peculiar in that it got set during qc
initialization and cleared if DMA mapping wasn't necessary.  Make it
more straight forward by making the following changes.

* Don't set it during initialization.  Set it after DMA is actually
  mapped.

* Add BUG_ON() to guarantee that there is data to transfer if DMAMAP
  is set.  This always holds for the current code.  The BUG_ON() is
  for docummentation and sanity check.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
---

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